How to disable auto-updates of /etc/hostsname, /etc/resolv.conf (& maybe others)?

[johnnyutahh]

PVE newbie here.

How do I disable the following "auto-change-files upon startup" behavior?

I have very-specific settings in /etc/hostname and /etc/resolv.conf (read: I know what I'm doing) in my Ubuntu 20.04 LXC container. PVE appears to be auto-changing values in these files upon every container restart/bootup. I have already removed the rdnssd resolvconf network-manager packages that tend to automatically-change files like the ones above.

PLS NOTE: I want to _keep_ the auto-configure-upon-creation behavior.

Also: how is this control (of files mentioned in the wiki reference below) different between LXC containers and kvm-based VMs?

A potentially-helpful reference:
https://pve.proxmox.com/wiki/Linux_Container#_guest_operating_system_configuration

 

[johnnyutahh]

Answering my own question (although I've not yet tested it), excerpt from the above-referenced wiki page:

Modification of a file can be prevented by adding a .pve-ignore. file for it. For instance, if the file /etc/.pve-ignore.hosts exists then the /etc/hosts file will not be touched. This can be a simple empty file created via:

# touch /etc/.pve-ignore.hosts

Most modifications are OS dependent, so they differ between different distributions and versions. You can completely disable modifications by manually setting the ostype to unmanaged.

 

[flove]

I also ran into this after migrating all my LXD Ubuntu containers to Proxmox including a powerDNS container which is a good example why this behaviour is unwanted in some scenarious.

If the container is configured for DHCP I would argue, this is unexpected behaviour.
I don't like Proxmox to handle my network configuration, especially not if containers are set to DHCP.

Is there a way to completely disable this on Proxmox host side instead of touching every container.

I ran into this again after installing tailscale on my proxmox host:
https://tailscale.com/kb/1133/proxmox/
https://www.reddit.com/r/Tailscale/comments/to3wj5/proxmox_and_tailscale_new_lxc_container_have_no/

sudo rm /etc/resolv.conf && sudo touch /etc/.pve-ignore.resolv.conf
# re-link systemd-resolve file
sudo ln -s /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf